In seismic exploration, it is well recognized that geophysical data is obtained by applying acoustic energy to the earth at the surface and detecting seismic energy reflected from reflecting interfaces of the subsurface formations. Unfortunately the data often contains noise that tends to obscure the signal or desired information that will help to pick out these interfaces of subterranean strata, among other desirable information.
The prior art has seen a wide variety of different approaches to employing theoretical equations to improve the signal-to-noise ratio. Illustrative of these type patents are the following:
U.S. Pat. No. 3,581,274; "Frequency-Domain Band Broadening of Seismic Data"; William H. Ruehle; U.S. Pat. No. 3,611,278; "Interval Velocity Determination"; Norman J. Guinzy and William H. Ruehle; and U.S. Pat. No. 3,622,967; "Optimum Stack"; Manus R. Foster and Raymond L. Sengbush. A plurality of references have been cited against these patents, also, but these type patents illustrate the use of theoretical equations for improving signal to noise ratio of recorded seismic data.
Exploration seismic data often is dominated by source generated energy whose propagation is confined to the near surface layers of the earth. This represents a form of coherent noise which can obscure reflections from deeper layers of interest to the explorationist. In conventional, single component seismology this coherent noise is suppressed through a variety of techniques including appropriate source and receiver arrays, low cut filters and spatial (f-k) filters.
The collection of multi-component data involves the recording of more than one source component and/or more than one receiver component for each source/receiver configuration in a survey. The additional components may provide supplementary information about the deep subsurface which can be of significant interest to the explorationist. A new application for these multi-component surveys is the reduction of coherent noise which may be afforded by an appropriate combination of different components.